Add system app icon and make use of it (thanks xphnx!)

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ####Next Version
 * Pebble: Allow installing apps compiled with SDK 2.x also on the balast platform (Time, Time Steel)
+* Some new and updated icons
 
 ####Version 0.6.9
 * Pebble: Store app details in pbw-cache and display them in app manager on firmware 3.x 

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/AppManagerActivity.java

@@ -73,8 +73,8 @@ public class AppManagerActivity extends Activity {
 
     private List<GBDeviceApp> getSystemApps() {
         List<GBDeviceApp> systemApps = new ArrayList<>();
-        systemApps.add(new GBDeviceApp(UUID.fromString("4dab81a6-d2fc-458a-992c-7a1f3b96a970"), "Sports (System)", "Pebble Inc.", "", GBDeviceApp.Type.UNKNOWN));
+        systemApps.add(new GBDeviceApp(UUID.fromString("4dab81a6-d2fc-458a-992c-7a1f3b96a970"), "Sports (System)", "Pebble Inc.", "", GBDeviceApp.Type.APP_SYSTEM));
-        systemApps.add(new GBDeviceApp(UUID.fromString("cf1e816a-9db0-4511-bbb8-f60c48ca8fac"), "Golf (System)", "Pebble Inc.", "", GBDeviceApp.Type.UNKNOWN));
+        systemApps.add(new GBDeviceApp(UUID.fromString("cf1e816a-9db0-4511-bbb8-f60c48ca8fac"), "Golf (System)", "Pebble Inc.", "", GBDeviceApp.Type.APP_SYSTEM));
 
         return systemApps;
     }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/adapter/GBDeviceAppAdapter.java

@@ -43,9 +43,15 @@ public class GBDeviceAppAdapter extends ArrayAdapter<GBDeviceApp> {
         deviceAppVersionAuthorLabel.setText(getContext().getString(R.string.appversion_by_creator, deviceApp.getVersion(), deviceApp.getCreator()));
         deviceAppNameLabel.setText(deviceApp.getName());
         switch (deviceApp.getType()) {
+            case APP_GENERIC:
+                deviceImageView.setImageResource(R.drawable.ic_watchapp);
+                break;
             case APP_ACTIVITYTRACKER:
                 deviceImageView.setImageResource(R.drawable.ic_activitytracker);
                 break;
+            case APP_SYSTEM:
+                deviceImageView.setImageResource(R.drawable.ic_systemapp);
+                break;
             case WATCHFACE:
                 deviceImageView.setImageResource(R.drawable.ic_watchface);
                 break;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/impl/GBDeviceApp.java

@@ -69,6 +69,7 @@ public class GBDeviceApp {
         WATCHFACE,
         APP_GENERIC,
         APP_ACTIVITYTRACKER,
+        APP_SYSTEM,
     }
 
     public JSONObject getJSON() {